It is estimated that across the world 30 million people are in need of prosthetic and orthotic devices. (“Guidelines for Training Personnel in Developing Countries for Prosthetics and Orthotics Services,” World Health Org., 2005; “World Report on Disability,” World Health Org., 2011; and S. Hamner, V. Narayan and K. Donaldson, “Designing for Scale: Development of the ReMotion Knee for Global Emerging Markets,” Ann. Biomed. Eng., vol. 41, no. 9, pp. 1851-1859, 2013, the relevant teachings of all of which are incorporated herein by reference in their entirety.)
A majority of amputees live in developing countries having large populations, such as India and China (Hamner et al.). According to an estimate by the World Health Organization, 90-95% of amputees in developing countries do not receive any prosthetic device (J. Andrysek, “Lower-limb prosthetic technologies in the developing world: A review of literature from 1994-2010,” Prosthet. Orthot. Int., vol. 34, no. 4, pp. 378-398, 2010, the relevant teachings of which are incorporated by reference in their entirety) and only 20% of the amputees are able to afford currently available prostheses in the market (D. Cummings, “Prosthetics in the developing world: a review of the literature,” Prosthet. Orthot. Int., vol. 20, no. 1, pp. 51-60, 1996, the relevant teachings of which are incorporated by reference in their entirety).
Current above-knee prostheses being distributed in the developing countries typically employ single-axis joints with or without manual locks. These prostheses often inhibit normative gait and suffer frequent mechanical failures resulting in low-user satisfaction (Andrysek et al).
Although a number of advanced prosthetic limbs and assistive devices have been designed in the developed world in the last few decades, very few of them have been suitable for large-scale use in developing countries due to vastly different and complex socio-economic considerations and resource-constrained settings. Passive knee joints commonly employed in developed countries, on the other hand, generally are considered to be too expensive to meet the requirements of amputees in the developing world.
Therefore, there is a need for a passive artificial knee that overcomes or minimizes the above-referenced problems.